flui
Simulations explained from the rule up. Every course here starts with one small rule you could follow by hand, runs it a few thousand times, and shows where the equation came from — rather than handing you the equation and asking you to trust it.
Everything runs live in the page. Nothing to install.
Simulation physics
Five courses, in order — each one earns the next
- 01 Boid movement Three steering rules per bird, and a flock nobody choreographed. The first course that follows individuals rather than a field.
- 02 Random walkers One blind coin flip per grain per tick. Count the crowd and the heat equation falls out of it — derived by counting, with one definition of calculus used three times.
- 03 Differential equations The pendulum that stops being a sine wave, phase portraits, and the shapes that survive when everything else fades. The vocabulary course.
- 04 Reaction–diffusion Two chemicals, one nonlinear term and a permanent supply line. The same operator that flattened the rod now grows spots, stripes and worms.
- 05 Incompressible flow A velocity field on a grid, and the pressure solve that keeps it honest. The Laplacian's third job: holding a fluid together.
Logic gates
A separate subject — no physics needed
Builds
Things that left the browser